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                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                                  Schedule TO
                     Tender Offer Statement under Section
          14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934

                                Microtest, Inc.
                           (Name of Subject Company)

                           Phoenix Acquisition Corp.
                              Danaher Corporation
                        (Name of Filing Person-Offeror)

                   Common Stock, Par Value $0.001 Per Share
                        Preferred Share Purchase Rights
                        (Title of Class of Securities)

                                   594941106
                     (CUSIP Number of Class of Securities)

                              Patrick W. Allender
                           Executive Vice President,
                     Chief Financial Officer and Secretary
                   2099 Pennsylvania Avenue, NW, 12th Floor
                          Washington, D.C. 20006-1813
                           Telephone: (202) 828-0850
           (Name, Address and Telephone Number of Person Authorized
      to Receive Notices and Communications on Behalf of Filing Persons)

                                   Copy to:

                             Mark A. Dewire, Esq.
                          Wilmer, Cutler & Pickering
                               2445 M Street, NW
                         Washington, D.C.  20037-1420
                           Telephone: (202) 663-6000

                           CALCULATION OF FILING FEE
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     Transaction Valuation*                           Amount of Filing Fee
--------------------------------------------------------------------------------
                $81,852,194                                      $16,371
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*    Based on the offer to purchase all of the outstanding shares of common
stock of Microtest, Inc. at a purchase price of $8.15 cash per share, 8,576,540
shares issued and outstanding, and outstanding options with respect to 1,466,674
shares (including 34,672 shares reserved for issuance under the Microtest, Inc.
Employee Stock Purchase Plan), in each case as of June 11, 2001.
[_]  Check box if any part of the fee is offset as provided by Rule 0- 11 (a)(2)
and identify the filing with which the offsetting fee was previously paid.
Identify the previous filing by registration statement number, or the Form or
Schedule and the date of its filing.
     Amount Previously Paid: None.
     Form or Registration No.: Not applicable.
     Filing Party: Not applicable.
     Date Filed: Not applicable.
[_]  Check the box if the filing relates solely to preliminary communications
     made before the commencement of a tender offer.
     Check the appropriate boxes below to designate any transactions to which
     the statement relates:
[x]  third-party tender offer subject to Rule 14d-1.
[_]  issuer tender offer subject to Rule 13e-4.
[_]  going-private transaction subject to Rule 13e-3.
[_]  amendment to Schedule 13D under Rule l3d-2.
     Check the following box if the filing is a final amendment reporting the
     results of the tender offer: [_]

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         This Tender Offer Statement on Schedule TO is filed by Danaher
Corporation, a Delaware corporation ("Danaher"), and Phoenix Acquisition Corp.,
a Delaware corporation and an indirect, wholly-owned subsidiary of Danaher (the
"Purchaser"). This Schedule TO relates to the offer by the Purchaser to purchase
all outstanding shares of common stock, par value $0.001 per share, including
the associated preferred share purchase rights, (the "Shares"), of Microtest,
Inc., a Delaware corporation ("Microtest") at $8.15 per Share, net to the seller
in cash, upon the terms and subject to the conditions set forth in the Offer to
Purchase, dated June 21, 2001 (the "Offer to Purchase") and in the related
Letter of Transmittal, copies of which are attached hereto as Exhibits (a)(1)
and (a)(2), respectively, (which, together with any amendments or supplements
thereto, collectively constitute the "Offer"). The information set forth in the
Offer to Purchase and in the related Letter of Transmittal is incorporated
herein by reference with respect to Items 1 through 9 and 11 of this Schedule
TO. The Agreement and Plan of Merger, dated as of June 12, 2001, among
Microtest, Danaher and the Purchaser, a copy of which is attached hereto as
Exhibit (d)(1), and the Confidentiality Agreement, dated February 25, 1999, by
and between Danaher and Microtest, as amended May 22, 2001, a copy of which is
attached hereto as Exhibit (d)(2), are each incorporated herein by reference
with respect to Items 5 and 11 of this Schedule TO.

Item 3.  Identity and Background of Filing Person.

         None of Danaher, the Purchaser or, to the best knowledge of such
corporations, any of the persons listed on Schedule I to the Offer to Purchase,
has during the last five years (i) been convicted in a criminal proceeding
(excluding traffic violations or similar misdemeanors) or (ii) been a party to
any judicial or administrative proceeding (except for matters that were
dismissed without sanction or settlement) that resulted in a judgment, decree or
final order enjoining the person from future violations of, or prohibiting
activities subject to, federal or state securities laws or finding any violation
of such laws.

Item 10. Financial Statements of Certain Bidders.

         Not applicable.

Item 12. Exhibits.

(a)(1)   Offer to Purchase, dated June 21, 2001.
(a)(2)   Form of Letter of Transmittal.
(a)(3)   Form of Notice of Guaranteed Delivery.
(a)(4)   Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies
         and Other Nominees.
(a)(5)   Form of Letter to Clients for use by Brokers, Dealers, Commercial
         Banks, Trust Companies and Other Nominees.
(a)(6)   Text of press release issued by Danaher dated June 13, 2001 (filed with
         the Securities and Exchange Commission under cover of Schedule TO-C by
         Danaher on June 13, 2001 and incorporated herein by reference).
(a)(7)   Text of press release issued by Fluke Networks, Inc. dated June 13,
         2001 (filed with the Securities and Exchange Commission under cover of
         Schedule TO-C by Danaher on June 13, 2001 and incorporated herein by
         reference).
(a)(8)   Guidelines for Certification of Taxpayer Identification Number on
         Substitute Form W-9.
(a)(9)   Form of summary advertisement dated June 21, 2001.
(d)(1)   Agreement and Plan of Merger, dated June 12, 2001, among Danaher, the
         Purchaser and Microtest.
(d)(2)   Confidentiality Agreement, dated February 25, 1999, between Danaher and
         Microtest, as amended May 22, 2001.
(g)      None.
(h)      Not applicable.
Item 13. Information Required by Schedule 13E-3.
         Not applicable.


                                   SIGNATURE

     After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Dated: June 21, 2001.

                                    PHOENIX ACQUISITION CORP.



                                    By:    /s/ Christopher C. McMahon
                                        ----------------------------------------
                                         Name: Christopher C. McMahon
                                         Title: Vice President and Secretary


                                    DANAHER CORPORATION



                                    By:    /s/ Patrick W. Allender
                                        ----------------------------------------
                                         Name: Patrick W. Allender
                                         Title: Executive Vice President,
                                         Chief Financial Officer and Secretary


                                 EXHIBIT INDEX

(a)(1)  Offer to Purchase, dated June 21, 2001.
(a)(2)  Form of Letter of Transmittal.
(a)(3)  Form of Notice of Guaranteed Delivery.
(a)(4)  Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies
        and Other Nominees.
(a)(5)  Form of Letter to Clients for use by Brokers, Dealers, Commercial Banks,
        Trust Companies and Other Nominees.
(a)(6)  Text of press release issued by Danaher dated June 13, 2001 (filed with
        the Securities and Exchange Commission under cover of Schedule TO-C by
        Danaher on June 13, 2001 and incorporated herein by reference).
(a)(7)  Text of press release issued by Fluke Networks, Inc. dated June 13, 2001
        (filed with the Securities and Exchange Commission under cover of
        Schedule TO-C by Danaher on June 13, 2001 and incorporated herein by
        reference).
(a)(8)  Guidelines for Certification of Taxpayer Identification Number on
        Substitute Form W-9.
(a)(9)  Form of summary advertisement dated June 21, 2001.
(d)(1)  Agreement and Plan of Merger, dated June 12, 2001, among Danaher, the
        Purchaser and Microtest.
(d)(2)  Confidentiality Agreement, dated February 25, 1999, between Danaher and
        Microtest, as amended May 22, 2001.
(g)     None.
(h)     Not applicable.